function ShowHide(id,aktion) {
		var itm = null;
		if (document.getElementById) 
			{
			itm = document.getElementById(id);
			} 
		else if (document.all) 
			{
			itm = document.all[id];
			} 
		else if (document.layers) 
			{
			itm = document.layers[id];
			}
	
		if (!itm) {
			// do nothing
			}
		else 
			if (itm.style) { 
				if (itm.style.display == "none" && aktion == 1) 
					{ 
					itm.style.display = ""; 
					}
				else if (aktion == 0)
					{ 
					itm.style.display = "none"; 
					}
				}
			else if (aktion == 1) 
				{ 
				itm.visibility = "show"; 
				}
	}
	
	function hideAll() {
		ShowHide('land_off',1);
		ShowHide('land_on',0);
	}